Tripoli: Four explosions rocked the Libyan capital on Tuesday as jets screamed in low over Tripoli on Tuesday carrying out unusually heavy bombardment for over three hours.

Four explosions rocked the Libyan capital shortly after 2:00 am (0000 GMT) on Tuesday, shaking the windows of a hotel housing journalists. They were quickly followed by two more blasts.

Sirens and shouts could be heard in the distance following the air strikes, as sporadic shots from assault rifles and heavier weapons rang out and jets continued to overfly the city.

Witnesses reported two explosions on Monday in the capital as jets flew overhead, adding that smoke was rising from a site near the offices of Libyan television and state news agency JANA.

At least one strike hit a building that had been previously bombed on April 30, a minder on a government-sponsored trip to the site said, adding that the building housed various civil society organisations.

The roof of part of the building was blown away along with one wall, and the basement was visible through the destroyed floor. A guard at the site said the building was hit around 11:00 pm (2100 GMT).

A soaring communications tower sits in a parking lot near the building.

On a later government-sponsored trip, a doctor at the Burn and Plastic Surgery Centre in the Shariah Zawiya area of Tripoli said that one young patient there was injured by glass from windows broken by one of the strikes.

A number of windows were shattered at the centre, as were those of nearby shops.

Journalists were not permitted to go to the actual site of the strike, which a minder said was a nearby building that used to be an intelligence headquarters but now housed the agriculture ministry.

The blasts came after NATO chief Anders Fogh Rasmussen said time was running out for Libyan leader Muammar Gaddafi, who "should realise sooner rather than later that there's no future for him or his regime."

An international coalition began carrying out strikes on pro-Gaddafi forces on March 19, under a UN resolution to protect civilians. NATO took command of operations over Libya on March 31.